While this security flaw likely affected few people (or no one at all), the latest update changes one important thing: it cannot be jailbroken. At least, currently, that's the case. Whether or not we'll see a jailbreak update for iOS 6.1.3 remains to be seen, but for now you should stick with iOS 6.1.2 unless you want to take another (potentially permanent) visit back to Apple's walled garden.